As an underwater device to be arranged under water, there have been conventionally known a submarine repeater which amplifies an optical signal transmitted through a submarine cable laid in the sea, a submarine branching unit which branches a submarine cable, and others. An underwater device has a feedthrough to keep water-tightness and air-tightness of a pressure-tight casing (see International Publication Pamphlet No. WO 2006/097972, Japanese Laid-Open Patent Publication No. 2002-142351, and Japanese Laid-Open Patent Publication No. 10-107702, for example).
Today, there is a movement to use a submarine cable as a cable for both telecommunications and monitoring. Such movement is referred to as “Green Repeater” in the International Telecommunication Union Telecommunication Standardization Sector (ITU-T).
A global monitoring network designed to monitor water temperatures, earthquakes, tsunamis, and the like is formed by underwater devices, which are one example of repeaters, equipped with measuring devices for measuring temperatures, pressure, acceleration and the like, for example. In the case where such a measuring device is attached to the exterior of a pressure-tight casing of an underwater device, a feedthrough placed in the pressure-tight casing is provided with a plurality of lead sections to be connected with electric wire cables such as a power wire, a ground wire, and a signal wire.
In this connection, techniques for connecting a cable coated with an insulating material to each of lead sections of a feedthrough include high frequency brazing, resistance brazing, crimping, and the like. After the connection with any of these connection techniques, the connected part is molded by an insulating material and thus is insulated. Note that the connection technique such as brazing, crimping, or the like mentioned above is often adopted instead of soldering, since the solder may melt when a molded part is hot.
A resistance brazing machine is used for resistance brazing work, and a high frequency coil is used for high frequency brazing work. In addition, a crimping tool is used for crimping connection work. If the resistance brazing machine, the high frequency coil, the crimping tool or the like is used with a space for using the tool blocked by the plurality of lead sections, cable connection work is difficult.
Note that a plurality of lead sections are provided to a single feedthrough in cases other than the case described above in which an underwater device is equipped with the measuring devices. For example, a plurality of lead sections may be provided to a single feedthrough also in a case where an underwater device is equipped with a device such as an underwater mateable connector or the like.